[XSL-LIST Mailing List Archive Home] [By Thread] [By Date]

# Re: [xsl] Word Ladders as an example of a "Find shortest path between two nodes in a graph" problem

 Subject: Re: [xsl] Word Ladders as an example of a "Find shortest path between two nodes in a graph" problem From: "Sean B. Durkin" Date: Tue, 27 Nov 2012 23:58:58 +1100

Dimitre,

I'm not making any claims about any alternatives being better or worse. I am just offering food for thought.

```Faithfully,
Sean.```

On 27/11/2012 11:50 PM, Dimitre Novatchev wrote:
On Tue, Nov 27, 2012 at 3:47 AM, Sean B. Durkin <sean@xxxxxxxxxxxxxxxxx> wrote:
Dimitre,

```In relation to the XPath 3.0 implementation of *my:HammingDistance*, here
are two alternatives.```

```_Alternative 1:__
_
fn:fold-left(
0,
function(\$distance, \$code-diff)
{
if (\$code-diff) then \$distance + 1
else \$distance
},
let \$c1 := string-to-codepoints(\$pStr1),
\$c2 := string-to-codepoints(\$pStr1) return
for \$i in 1 .. min(count(\$c1),count(\$c2)) return
\$c1[\$i] - \$c2[\$i]
)```

__Alternative_ 2:__

```_count(
let \$c1 := string-to-codepoints(\$pStr1),
\$c2 := string-to-codepoints(\$pStr1) return
for \$i in 1 .. min(count(\$c1),count(\$c2)) return
1[\$c1[\$i] eq \$c2[\$i]]
)```

The count() function in alternative 2 could equally well be sum().

```I'm not making any claims about the relative merits of these alternatives --
just providing some food for thought.
```

Sean,

Why do you think these are better than:

```<xsl:sequence select=
bcount(map-pairs(f:eq#2,
string-to-codepoints(\$pStr1),
string-to-codepoints(\$pStr2)
)
[not(.)]
)
b/>```

?

```I am planning on what I hope will be significantly optimized Hamming
distance implementation -- probably in a next post.```

```Cheers,
Dimitre```

```Faithfully,
Sean B. Durkin```

On 27/11/2012 4:08 PM, Dimitre Novatchev wrote:
Dear XSLT professionals,

```In case you are interested in solving the Word Ladders problem first
formulated by Lewis Carroll, or just in an XSLT solution of the "Find
shortest path in graph" problem, you might be interested to have a
look at the implementation in my latest blog post:```

```Any feedback about this implementation and suggestions for further